Isoflurane: Mechanisms and applications

Sio, Lady Christine Ong; Varbanova, Marina; Bautista, Alexander

doi:10.1016/b978-0-12-820237-1.00011-9

Cited by 2 publications

(2 citation statements)

References 15 publications

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“…Isoflurane administered in G 4 rats is a volatile anesthetic that causes depression in the cardiorespiratory centers, leading to hypoxemia and death [ 26 , 60 ]. Although isoflurane has been considered as a method of CO 2 euthanasia refinement [ 14 , 15 ], in comparison with CO 2 and other volatile anesthetics, isoflurane has mild pungency [ 61 ], causing more aversion responses in laboratory rodents that is possibly due to airway irritation [ 52 , 62 ], air hunger, and dyspnea [ 52 ].…”

Section: Discussionmentioning

confidence: 99%

Thermal Response of Laboratory Rats (Rattus norvegicus) during the Application of Six Methods of Euthanasia Assessed by Infrared Thermography

Domínguez-Oliva,

Hernández-Ávalos,

Olmos-Hernández

et al. 2023

Animals

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Refinement is one of the principles aiming to promote welfare in research animals. The techniques used during an experimental protocol, including euthanasia selection, must prevent and minimize suffering. Although the current euthanasia methods applied to laboratory rodents are accepted, the controversial findings regarding the potential stress/distress they can cause is a field of research. The objective was to assess the thermal response of Wistar rats during various euthanasia methods using infrared thermography (IRT) to determine the method that prevents or diminishes the stress response and prolonged suffering. Pentobarbital (G1), CO2 (G2), decapitation (G3), isoflurane (G4), ketamine + xylazine (G5), and ketamine + CO2 (G6) were evaluated at five evaluation times with IRT to identify changes in the surface temperature of four anatomical regions: ocular (T°ocu), auricular (T°ear), interscapular (T°dor), and caudal (T°tai). Significant differences (p < 0.05) were found in G2 and G4, registering temperature increases from the administration of the drug to the cessation of respiratory rate and heart rate. Particularly, isoflurane showed a marked thermal response in T°ocu, T°ear, T°dor, and T°tai, suggesting that, in general, inhalant euthanasia methods induce stress in rats and that isoflurane might potentially cause distress, an effect that must be considered when deciding humane euthanasia methods in laboratory rodents.

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Section: Discussionmentioning

confidence: 99%

Thermal Response of Laboratory Rats (Rattus norvegicus) during the Application of Six Methods of Euthanasia Assessed by Infrared Thermography

Domínguez-Oliva,

Hernández-Ávalos,

Olmos-Hernández

et al. 2023

Animals

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“…Considering the available literature regarding isoflurane anesthesia and the application of the RGS, additional studies are necessary to determine if, during euthanasia, the high RGS score found in Iso rats could be completely associated with stress, pain, or might be a pharmacological effect of isoflurane. In this sense, isoflurane inhibits acetylcholine receptors, causing dose-dependent muscle relaxation of both skeletal and smooth muscles [75]. This property could influence the innervation of mimetic muscles used to evaluate facial expressions in rodents, as presented in this research.…”

Section: Discussionmentioning

confidence: 88%

Rat Grimace Scale as a Method to Evaluate Animal Welfare, Nociception, and Quality of the Euthanasia Method of Wistar Rats

Domínguez-Oliva,

Olmos-Hernández,

Hernández-Ávalos

et al. 2023

Animals

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Refinement of experimental procedures in animal research has the objective of preventing and minimizing pain/distress in animals, including the euthanasia period. This study aimed to evaluate pain associated with six methods of euthanasia in Wistar rats (injectable, inhalational, and physical), by applying the Rat Grimace Scale (RGS), comparing the scores, and determining the method with the highest score that might indicate pain for laboratory rodents. Sixty adult male and female Wistar rats were used and assigned to six treatments: pentobarbital, CO2, decapitation, isoflurane, ketamine + xylazine, and ketamine + CO2. Video recording to assess the RGS scores was performed in four events: basal: 24 h before the procedure; Ti1: three minutes before the procedure; Ti2: during the application of the euthanasia method; and Ti3: immediately after the application until LORR. The main findings of this study showed that, during Ti2, decapitation and ketamine + xylazine had the highest scores (0.6 ± 0.26 and 0.6 ± 0.16, respectively) (p < 0.0001), while at Ti3, CO2 (0.9 ± 0.18) and isoflurane (1.2 ± 0.20) recorded the highest scores (p < 0.0001). According to the present results, decapitation and ketamine + xylazine elicited short-term acute pain, possibly due to tissue damage caused by both methods (injection and guillotine). In contrast, isoflurane’s RGS scores recorded during Ti3 might be associated with nociception/pain due to the pungency of the drug or to the pharmacological muscle relaxant effect of isoflurane. Further research is needed to establish a comprehensive study of pain during euthanasia, where RGS could be used minding the limitations that anesthetics might have on facial expression.

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Isoflurane: Mechanisms and applications

Cited by 2 publications

References 15 publications

Thermal Response of Laboratory Rats (Rattus norvegicus) during the Application of Six Methods of Euthanasia Assessed by Infrared Thermography

Thermal Response of Laboratory Rats (Rattus norvegicus) during the Application of Six Methods of Euthanasia Assessed by Infrared Thermography

Rat Grimace Scale as a Method to Evaluate Animal Welfare, Nociception, and Quality of the Euthanasia Method of Wistar Rats

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